Parts of a Controlled Experiment Interactive Notes

A gardener noticed that her plants were not growing as fast as they did in the previous year. She decided to see if she could help her plants grow faster. When she went to the nursery, she found three fertilizers available for her plants. One of those fertilizers, fertilizer A, was recommended to her because it had been known to help plants grow the best. However, she decided to conduct a test to determine which of the three fertilizers, if any, helped her plants grow fastest. The gardener planted four seeds, each in a separate pot. She used the same type of pot and the same type of soil in each pot. She fertilized one seed with fertilizer A, one with fertilizer B, and one with fertilizer C. She did not fertilize the fourth seed. She placed the four pots near one another in her garden. She made sure to give each plant the same amount of water each day. She measured the height of the plants each week and recorded her data. After eight weeks of careful observation and record-keeping, she had the following table of data.

  1. What observations did the gardener have?
  1. What question is she investigating?
  1. Did she have any background knowledge or research to help her design her experiment? If so, what was it?
  1. Does she have a hypothesis? ______If so, what is it?
  1. Write a hypothesis by filling in the statement: I think that ______will cause the plants to ______
  1. What is the gardenersindependentvariable? ______

What is your evidence?

  1. What is the gardeners dependent variable? ______

What is your evidence?

  1. List the variable factors that the gardener kept constant. (key word SAME)
  1. Does the gardener have a control group? ______If so, what is it?
  1. How does having acontrol group make this experiment more reliable?
  2. Analyze the data by putting the plants in order from the most growth to the least growth
  1. Color & Label the lines on the graph with the corresponding fertilizer (A, B, C, CONTROL)

  1. Analyze the graph by describing any patterns you see.
  1. What inference/conclusion should the gardener make based on the data?
  1. What evidence can you use from the data to justifythe inference?
  1. Suppose fertilizer B is much more expensive than fertilizer A & C. How might this affect which fertilizer the gardener should buy?
  1. What are some things you could be skeptical about with the gardener’s data? (Is her data reliable enough to communicate this data to other gardeners)